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f2fs: clean up foreground GC flow

PATCH New Chao Yu 1 participant 2 messages Aug 19, 2016 F2FS file system

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Chao Yu

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#0 lore raw

PATCH 1/2 f2fs: clean up foreground GC flow

From: Chao Yu <[email protected]>

This patch changes to check valid block number of one GCed section directly instead of checking the number in all segments of section one by one in order to clean up codes of foreground GC.

Signed-off-by Chao Yu <[email protected]>
---
 fs/f2fs/gc.c | 19 ++++++++-----------
 1 file changed, 8 insertions(+), 11 deletions(-)
fs/f2fs/gc.c +8 -11
index 8f7fa32..c1599b4 100644
@@ -815,7 +815,7 @@ static int do_garbage_collect(struct f2fs_sb_info *sbi,
 	struct blk_plug plug;
 	unsigned int segno = start_segno;
 	unsigned int end_segno = start_segno + sbi->segs_per_sec;
-	int seg_freed = 0;
+	int sec_freed = 0;
 	unsigned char type = IS_DATASEG(get_seg_entry(sbi, segno)->type) ?
 						SUM_TYPE_DATA : SUM_TYPE_NODE;
 

@@ -871,22 +871,20 @@ static int do_garbage_collect(struct f2fs_sb_info *sbi,
 
 	blk_finish_plug(&plug);
 
-	if (gc_type == FG_GC) {
-		while (start_segno < end_segno)
-			if (get_valid_blocks(sbi, start_segno++, 1) == 0)
-				seg_freed++;
-	}
+	if (gc_type == FG_GC &&
+		get_valid_blocks(sbi, start_segno, sbi->segs_per_sec) == 0)
+		sec_freed = 1;
 
 	stat_inc_call_count(sbi->stat_info);
 
-	return seg_freed;
+	return sec_freed;
 }
 
 int f2fs_gc(struct f2fs_sb_info *sbi, bool sync)
 {
 	unsigned int segno;
 	int gc_type = sync ? FG_GC : BG_GC;
-	int sec_freed = 0, seg_freed;
+	int sec_freed = 0;
 	int ret = -EINVAL;
 	struct cp_control cpc;
 	struct gc_inode_list gc_list = {

@@ -925,9 +923,8 @@ gc_more:
 		goto stop;
 	ret = 0;
 
-	seg_freed = do_garbage_collect(sbi, segno, &gc_list, gc_type);
-
-	if (gc_type == FG_GC && seg_freed == sbi->segs_per_sec)
+	if (do_garbage_collect(sbi, segno, &gc_list, gc_type) &&
+			gc_type == FG_GC)
 		sec_freed++;
 
 	if (gc_type == FG_GC)
Signature · 1 line
2.7.2
author maintainer
#1 lore raw

PATCH 2/2 f2fs: avoid unneeded loop in build_sit_entries

From: Chao Yu <[email protected]>

When building each sit entry in cache, firstly, we will load it from sit page, and then check all entries in sit journal, if there is one updated entry in journal, cover cached entry with the journaled one.

Actually, most of check operation is unneeded since we only need to update cached entries with journaled entries in batch, so changing the flow as below for more efficient:
1. load all sit entries into cache from sit pages;
2. update sit entries with journal.

Signed-off-by Chao Yu <[email protected]>
---
 fs/f2fs/segment.c | 48 ++++++++++++++++++++++++++++++++----------------
 1 file changed, 32 insertions(+), 16 deletions(-)
fs/f2fs/segment.c +32 -16
index 59f578b..a394012 100644
@@ -2262,22 +2262,11 @@ static void build_sit_entries(struct f2fs_sb_info *sbi)
 			struct f2fs_sit_entry sit;
 			struct page *page;
 
-			down_read(&curseg->journal_rwsem);
-			for (i = 0; i < sits_in_cursum(journal); i++) {
-				if (le32_to_cpu(segno_in_journal(journal, i))
-								== start) {
-					sit = sit_in_journal(journal, i);
-					up_read(&curseg->journal_rwsem);
-					goto got_it;
-				}
-			}
-			up_read(&curseg->journal_rwsem);
-
 			page = get_current_sit_page(sbi, start);
 			sit_blk = (struct f2fs_sit_block *)page_address(page);
 			sit = sit_blk->entries[SIT_ENTRY_OFFSET(sit_i, start)];
 			f2fs_put_page(page, 1);
-got_it:
+
 			check_block_count(sbi, start, &sit);
 			seg_info_from_raw_sit(se, &sit);
 

@@ -2289,13 +2278,40 @@ got_it:
 							se->valid_blocks;
 			}
 
-			if (sbi->segs_per_sec > 1) {
-				struct sec_entry *e = get_sec_entry(sbi, start);
-				e->valid_blocks += se->valid_blocks;
-			}
+			if (sbi->segs_per_sec > 1)
+				get_sec_entry(sbi, start)->valid_blocks +=
+							se->valid_blocks;
 		}
 		start_blk += readed;
 	} while (start_blk < sit_blk_cnt);
+
+	down_read(&curseg->journal_rwsem);
+	for (i = 0; i < sits_in_cursum(journal); i++) {
+		struct f2fs_sit_entry sit;
+		struct seg_entry *se;
+		unsigned int old_valid_blocks;
+
+		start = le32_to_cpu(segno_in_journal(journal, i));
+		se = &sit_i->sentries[start];
+		sit = sit_in_journal(journal, i);
+
+		old_valid_blocks = se->valid_blocks;
+
+		check_block_count(sbi, start, &sit);
+		seg_info_from_raw_sit(se, &sit);
+
+		if (f2fs_discard_en(sbi)) {
+			memcpy(se->discard_map, se->cur_valid_map,
+						SIT_VBLOCK_MAP_SIZE);
+			sbi->discard_blks += old_valid_blocks -
+						se->valid_blocks;
+		}
+
+		if (sbi->segs_per_sec > 1)
+			get_sec_entry(sbi, start)->valid_blocks +=
+				se->valid_blocks - old_valid_blocks;
+	}
+	up_read(&curseg->journal_rwsem);
 }
 
 static void init_free_segmap(struct f2fs_sb_info *sbi)
Signature · 1 line
2.7.2